197  
ACUS11 KWNS 182015  
SWOMCD  
SPC MCD 182015  
SDZ000-182215-  
 
MESOSCALE DISCUSSION 1985  
NWS STORM PREDICTION CENTER NORMAN OK  
0315 PM CDT MON AUG 18 2025  
 
AREAS AFFECTED...WESTERN SOUTH DAKOTA  
 
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE  
 
VALID 182015Z - 182215Z  
 
PROBABILITY OF WATCH ISSUANCE...40 PERCENT  
 
SUMMARY...STORMS MAY PRODUCE LARGE HAIL AND SEVERE WINDS THIS  
AFTERNOON. STORM COVERAGE REMAINS UNCERTAIN, BUT A WATCH IS POSSIBLE  
DEPENDING ON CONVECTIVE TRENDS.  
 
DISCUSSION...A SUPERCELL HAS DEVELOPED AND INTENSIFIED IN THE BLACK  
HILLS AND IS CURRENTLY PROGRESSING SOUTHEASTWARD. WITH 7.8 C/KM  
MID-LEVEL LAPSE RATE SAMPLED BY THE OBSERVED 18Z RAP SOUNDING AND  
THE STORM MOVING INTO MODESTLY GREATER SHEAR, IT IS PROBABLE THIS  
STORM WILL CONTINUE INTO THE AFTERNOON. ADDITIONAL CUMULUS ARE  
DEEPENING ALONG A SURFACE BOUNDARY IN NORTHERN SOUTH DAKOTA.  
ADDITIONAL STORMS MAY FORM WITHIN THE NEXT COUPLE OF HOURS. THE MAIN  
UNCERTAINTY WILL BE THE COVERAGE OF STORMS. THIS REGION IS IN THE  
WAKE OF A SHORTWAVE TROUGH NOW IN EASTERN NORTH DAKOTA PER WATER  
VAPOR IMAGERY. THAT, ALONG WITH RISING MID-LEVEL HEIGHTS, MAY MEAN  
STORMS REMAIN ISOLATED. THOSE THAT DO DEVELOP WILL BE CAPABLE OF  
LARGE HAIL AND SEVERE WINDS, ESPECIALLY WITH SOUTHERN EXTENT.  
 
..WENDT/MOSIER.. 08/18/2025  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...ABR...UNR...  
 
LAT...LON 44020373 44520381 45590280 45460115 44790075 43730145  
43520272 43720371 44020373  
 
MOST PROBABLE PEAK WIND GUST...65-80 MPH  
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN  
 
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